(1) Field of Invention
The present invention relates to a series of novel phosphated silicone polymers which are substantive to fiber and provide antistatic properties to various fibers. The compounds, because they containg a pendant ionizable phosphate group provide the desired antistatic and lubrication properties to the fiber. Since the compounds of the present invention are high molecular weight silicone polymers, they have a high degree of oxidative stability, even at elevated temperatures. In addition, these compounds are non volatile. These combination of properties makes these polymers ideally suited for use as fiber lubricants/antistats. The compounds of the present invention are also stable to alkaline solutions, unlike the hydroxy containing silicone polymers from which they are made.
The compounds of the present invention are prepared by the phosphation of a pendant hydroxyl group which is present on a silicone polymer. In a preferred embodiment the hydroxy containing silicone polymer has been alkoxylated with ethylene oxide, propylene oxide, butylene oxide or mixtures thereof. The ability regulate the type of alkylene oxide and amount present in the silicone polymer results in a series of products ranging in water/oil solubility. The technology used to produce the compounds of the present invention is very flexible and allows us to prepare performance tailored molecules for specific applications.
(2) Object of the Invention
It is the object of the present invention to provide a series of novel phosphated silicone polymers, which are substantive to the surface of a fibers. This substantivity results in antistatic properties and lubricity. The superior antistatic properties of the compounds of the present invention are an important benefit, since this is a major aspect of fiber lubrication.
It is another objective of the current invention to provide phosphated silicone polymers which have very low volatility. Volatility is a major concern in formulating fiber lubricants. This is due to the fact that fiber lubricants are exposed to high temperatures during processing. Volatile lubricants, like non-silicone based phosphate esters, evaporate from the fiber and go into the air. This results not only in loss of efficency and high costs, but potential enviromental contamination in the workplace. Still another object of the present invention is to provide a series of phosphated silicone polymers which have differing solubilities in water and organic solvents. This is achieved by selection of the hydroxy silicone polymer used as a raw material.
Application of the compounds of the invention can be from solvent, aqueous dispersion or solution, or applied neat in these processes.
The silicone polymers, suitable as raw materials, in a preferred embodiment, contain varying amounts of ethylene oxide, propylene oxide or butylene oxide or mixtures thereof. The presence of the oxide in the phosphated silicone polymer results in compounds with an inverse cloud point. Inverse cloud point phenomenon are well known to those skilled in the art of nonionic surface active agents. The inverse cloud point is defined as a temperature above which the polymer has minimal solubility in water. If heat is aplied to an aqueous solution of the nonionic at the inverse cloud point the material will become insoluble, and the solution will turn milky. It is at this point that the polymer has minimal water solubility. Since the product is no longer in solution at above this temperature, it is within this temperature range that the product has maximum substantivity to a fiber. The ability to use temperature to deposit a lubricant, antistat onto a fiber offers a great advantage in cost effectiveness of fiber treatment, and results in less product usage.
(3) Description of the Arts and Practices
Silicone oils (dimthylpolysiloxane) have been known to be active at the surface of plastic, cellulosic and synthetic fibers as well as paper. Despite the fact that they are lubricants that are stable to oxidation, their high cost and lack of durability has made them cost prohibitive in most application areas. Silicone oils need to be emulsified prior to application. This requires high pressure equipment, surface active agents and generally results in a milky emlsion. Emulsions have experienced stability problems both in terms of freeze thaw instability and upon heating. This has resulted in minimal acceptance of them in commercial products.
The low efficiency of silicone oils is due to the fact that the oil is very water insoluble. Emulsions are generally prepared which contain silicone dispersed in micelles. While this method of application is easier for processing, much of the oil stays in the surfactant micelle and never gets deposited on the fiber. That which does deposit on the fiber surface remains there by hydrophobic binding, not ionic bonding. Since the polydimethylsiloxane is not ionically bonded the effect is very transient. The product is removed with one washing.
Fatty alcohol phosphate esters have been known fiber lubricants for many years. They have a much lower molecular weight than the silicone based compounds of the present invention. For this reason, they are much more volatile and cannot be used in high temperature fiber applications. The standard fatty phosphate esters used in fiber lubricant formulations, are not as efficient as those based upon silicone polymers.
Many attempts have been made to overcome these problems and get a truly substantive non volatile product, which deposits on fiber efficiently. One approach has been to use hydrosilation technology to make alkoxylated silicone polymers, used as raw materials in this invention. These materials do not have the substantivity desired to make them suitable for use as fiber lubricants or antistats. It was not until the compounds of the present invention that the desirable lubrication and low volatility of silicone could be effectively used in a fiber lubricant system by incorporation of a phosphate group onto the polymer backbone U.S. Pat. No. 3,511,699 to Sterman issued May 12, 1970 teaches that epoxy compounds placed in the silicone backbone by hydrosilation can be cured onto certain fibers to give improved substantivity. The substantivity is based upon the reaction of hydroxyl groups on the cellulosic and the epoxy group in the silicone polymer. The resulting bond is a ether linkage and a new hydroxyl group. While a definite improvement over other compounds the efficiency and durability of the were not good enough to allow for cost effective incorporation of these materials in detergent formulations.